Telecommunications networks that provide wireless access (e.g. GSM, UMTS, WiMax, LTE) have developed tremendously over the past years. In such networks, voice and data services can be provided to user equipment having a high mobility, i.e. the communication devices are not bound to a particular location and are freely movable through the area covered by the network. A gateway node of the telecommunications network enables connection to a further network, for example a network based on IP such as the internet.
The availability of such a telecommunications network connected to the further network has resulted in demands for further services, including services that relate to so-called machine-to-machine (M2M) communications, also referred to as machine-type communications (MTC). The service requirements for MTC are currently being standardized in 3GPP (see e.g. TS 22.368). MTC applications typically involve hundreds, thousands or millions of user equipment (MTC devices) which each act as a user equipment to the telecommunication network. Such MTC devices may be stationary or non-stationary. An example involves the electronic reading of e.g. ‘smart’ electricity meters at the homes of a large customer base over the telecommunications network from a server connected to a further network. Other examples include sensors, meters, vending or coffee machines, car meters for route pricing applications, navigation equipment etc. that can be equipped with communication modules that allow exchanging information with other equipment, such as a data processing centre over the telecommunications network.
An important dimensioning parameter for control plane nodes in the wireless telecommunications networks is the number of simultaneously attached/registered user equipment.
Since MTC typically involves a very large number of MTC devices that send/receive only a low amount of user plane data, the use of control plane resources needed for these MTC devices is high compared to the user plane data that is normally the basis for pricing. The absorbed capacity and costs associated with large numbers of MTC devices are therefore high compared to the actual use and turnover. Solutions to mitigate the burden of keeping high amounts of MTC devices registered in the network would be beneficial.
The issue of registering large numbers of MTC devices in the telecommunications network has been recognized and discussed in various 3GPP working groups. In a potential solution described in 3GPP TR 23.888, an MTC device would not be registered in the telecommunications network when it does not communicate. The MTC device will attach and connect to the network when triggered from the network. The trigger involves enabling the MTC device to listen to a broadcast channel (e.g. a cell broadcast channel) while not being attached to the network. Triggers to the MTC device to establish communication are broadcasted over the broadcast channel. The MTC device(s) for which the broadcasted message/trigger is intended is (are) configured to recognize the message. In this way, network resources associated with registering a large number of MTC devices in the network are saved.
However, non-registration of the MTC devices in the telecommunications network may be disadvantageous in certain cases. For example, the transmission of a cell broadcast signal may be inefficient if only a limited number of MTC devices are distributed over a large number of cells of the network and broadcast resources are wasted in view of the limited number of MTC devices to be triggered.